Air handling systems require air filtration to remove foreign particulates prior to supplying air to an area. Filters also protect expensive components within the air ventilating unit. The air filtration system is generally composed of air filters available in various sizes, and an assembly which retains the filter(s) in place. Air filters are inserted into sized cavities of the assembly, secured in place with retainers and sealed against the assembly to prevent air bypassing or leaking around the filters.
Conventional filter retaining assemblies are designed for nominal filter sizes. Filter nominal sizes are larger than the actual physical dimensions, and designing filter cavities based on nominal sizes instead of actual dimensions leads to a larger than needed foot print and poses challenges when faced with air handling unit size restrictions. Prior art air filter retaining assemblies are constructed by welding corner pieces for one individual filter cavity frame. Assembly filter cavities are lined with a gasket where air filters are held against the frame to provide sealing. Each cavity includes retainers along the sides of the frame to hold and secure air filters in place. The individual frames are aligned through the use of indentations or guide holes on each frame and fastened together using rivets, screws or other fasteners. Additionally, larger filter assemblies typically require stiffener bars, leading to additional use of equipment and time. The installation of stiffener bars on the assembly may blank off sections of filters where the full effective face of the filter array is not utilized and therefore efficiency is reduced.
When faced with dimensional constraints for an air handling unit with specific performance requirements, there is a need to keep filter rack assemblies as compact as possible to fit into the unit. This is particularly true as filter racks are usually one of the main driving factors of air handing units' cross sectional dimensions. Therefore, there is a need for a more compact and rigid filter assembly to fit into the valuable space within the physical confines of the air handling unit.